Production and Evaluation of Recombinant Subunit Vaccine Against Swine Enzootic Pneumonia

by Conceição, Fabrício Rochedo

Abstract (Summary)

SUMMARYCONCEIÇÃO, FABRICIO ROCHEDO, Universidade Federal de Pelotas, may2005. Production and Evaluation of Recombinant Subunit Vaccine AgainstSwine Enzootic Pneumonia. Advisor: Odir Antônio Dellagostin. Co-Advisor:Swine Enzootic Pneumonia (SEP), caused by bacterium Mycoplasmahyopneumoniae, is the most important respiratory disease in swine breeding.The commonly used vaccines to control this disease consist of bacterins, whoseproduction cost is high and the efficiency is limited. The objective of this studywas to develop and to evaluate a new alternative for controlling SEP, based ona recombinant subunit vaccine (rLTBR1) containing the R1 region of P97adhesin of Mycoplasma hyopneumoniae (R1) fused to the B subunit of the heat-labileenterotoxin of Escherichia coli (LTB). rLTBR1 formed functional oligomersthat presented high affinity to GM1 ganglioside. Mice inoculated with rLTBR1(IN or IM) produced high levels of anti-R1 systemic and mucosal (sIgA)antibodies, which recognized the native P97. On the other hand, miceinoculated with the commercial bacterin did not produce anti-R1 antibodies. Theadministration route influenced the modulation of the immune response by LTB,showing that IM rLTBR1 induced Th2-biased immune responses and INrLTBR1 induced Th1-biased immune responses. IN rLTBR1 also induced IFN-?secretion by lymphocytes. The rLTB showed to be a powerful mucosal adjuvant,stimulating the production of anti-R1 IgA in trachea and bronchi from miceinoculated with rLTBR1 by parenteral route (IM). rLTBR1 may constitute a newstrategy for preventing infection by Mycoplasma hyopneumoniae and may havepotential for developing vaccines against other infectious diseases as well. Nowa day, the efficacy of this vaccine is being evaluated in specific pathogen freeswine.